Of the 47 pools and spas that have been closed, nine continued to have problems when inspectors returned and either were not allowed to reopen or were forced to close again.

Many of the pools had little or no chlorine, some had pH imbalances and in others, water did not flow adequately through the system -- conditions that if left unattended, could result in health risks to swimmers.

"Public pools have to be monitored frequently," said Ronald D. Warner, associate professor of epidemiology, preventive medicine and public health at the Texas Tech University Health Sciences Center. "A lot of people use them, and they bring their germs, dirt and debris with them."

The result, if chlorine and pH levels are not maintained, could be skin irritation, ear and eye infections, diarrhea and other illnesses, according to the Centers for Disease Control and Prevention in Atlanta.

On July 3, a 7-year-old boy drowned and his body lay at the bottom of a hotel pool in Osceola County for two hours before anyone noticed. A maintenance worker said visibility in the water had been diminished. The pool had been shut down six times in the past seven years because of poor water quality.

Still, health officials emphasized that a pool closing doesn't necessarily mean maintenance is lacking or the water is dangerous.

While such closings can indicate the potential for problems and must be taken seriously, most community pools probably are safer than backyard pools where chlorine and pH levels do not have to be professionally monitored, said Kevin Lenhart, program operations administrator for the Lake County Health Department.

Lake community pools that typically have the most problems, Health Department officials say, are those with old equipment and outdated plumbing -- often, pools in older mobile-home parks and hotels.

The Guest House Inn in Leesburg, for example, was a Holiday Inn in the 1970s, said current owner and manager Bill Flynn. He said the age of the pool has caused so many problems that he has decided to renovate it.

Health Department records show the pool was closed June 15. Inspectors found it had no chlorine and the rate of water flow was less than half of what it should have been. The following week, on June 23, inspectors noted it still had no chlorine.

Inspectors came out the next day and again June 27, giving the pool an "unsatisfactory" rating each time because of insufficient water flow. On July 6, records show the pool was shut down again, and the operating permit was not renewed.

Flynn said he has voluntarily closed the pool on occasion while workers tried to remedy problems.

"We're trying to do the right thing," he said. "We put in an $800 pump two weeks ago and that didn't fix the problem. It has been a real headache."

The water last week looked clear from a distance with the sunlight sparkling off the surface, but caution tape surrounded the perimeter and a "closed" sign was posted on the gate.

Such warnings alert swimmers to potential problems, but how can consumers be sure that pools without posted signs are safe?

"The clarity of the water is a big sign," said Russ Melling, environmental manager at the Lake County Health Department.

State inspectors routinely check that ladders are securely fastened to pool walls, safety equipment is present and rules and warnings are properly posted.

Primarily, though, they check the level of chlorine, the pH balance (a measure of the acidity or alkalinity of the water), the rate of water flow and the amount of chlorine stabilizer in the pool. A violation in any of those areas can result in automatic closing. That's because such problems could allow bacteria to grow in the water, exposing users to infection, illness and, in extreme cases, death.

In 1998, a 2-year-old girl died from complications of an E. coli infection she contracted at a water park in Atlanta. She was one of 26 children who became infected at White Water Park on one of four days that June.

So far, Lake County has been fortunate.

Health Department officials said they were not aware of any such outbreaks or infections from community pools in the county, even though every year pools receive unsatisfactory ratings or are required to close.

"An unsatisfactory rating or closing doesn't mean there is a health risk or that people will get sick swimming in the water, but the potential is there," Lenhart said. "In most cases, the owners just correct the problem and move on."